Prevalence of congenital-nevus-like nevi, nevi spili, and café au lait spots.

To determine the clinical prevalence of medium-sized (1.5- to 19.9-cm-diameter) congenital-nevus-like nevi (CNLN), a consecutive series of 601 patients (mostly adults) had total cutaneous examinations. In this series, 15 (2.5%) were found to have such lesions. In addition, 14 (2.3%) had nevi spili and 83 (13.8%) had café au lait spots. All three types of lesions were equally represented in both sexes and tended to spare the head, neck, and upper extremities. Compared with CNLN, nevi spili were found to have significantly larger diameters and lower mean age, suggesting that these are different types of lesions. Some recommend the surgical removal of all congenital nevocytic nevi because of their malignant potential. Since it is not possible to clinically distinguish congenital nevocytic nevi and CNLN and since the observed prevalence of these lesions in adults is over four times that previously reported in newborns, such a recommendation becomes less feasible.